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Chapters 14-17
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Change over time Spontaneous Generation: Living organisms arise from non-living things. Many experiments were conducted to disprove spontaneous generation.
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SCIENTISTDISPUTED THEORY CONCLUSIONS Francesco Redi (1600’s) Maggots come from rotting meat Maggots come from eggs laid by flies Lazzaro Spallanzani (1700’s) Microorganisms come from a vital force in the air Microorganisms travel in the air Louis Pasteur (1800’s) Boiling destroys air’s vital force Solid particles in the air transport microorganisms.
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Redi—Spallanzani—
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Pasteur--
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Formation of Simple Organic Compounds Alexander Oparin, 1923 (H2O, H2, CH4, & NH3) Formation of Complex Organic Compounds Amino acids formed chains in early atmosphere Concentration & Enclosure of Organic Compounds Coacervates & Microsphere formed Evolution of Growth, Metabolism, & Reproduction
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Approximately 4.6 – 3.5 billion years ago. First organisms – Prokaryotic cells Eukaryotic cells – 1 billion years ago Endosymbiont Theory – Eukaryotic mitochondria evolved from bacteria & chloroplasts evolved from cyanobacteria.
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We can find evidence of evolution by examining fossils & modern day organisms
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Dating fossils Carbon-dating Position in sedimentary rock Formation of the Fossil Record Types of fossils: Mold Cast Imprint
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Common ancestry Hawaiian honeycreepers Homologous structures Similar embryologically, but have different functions Vestigial organs Functionless parts Biochemistry Similar biochemical metabolism Embryological Development Fish, rabbits, gorilla
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Jean Baptiste de Lamarck (1774-1829) Before Darwin Inheritance of Acquired Characteristics “If you don’t use it, you lose it” Natural Selection Organisms with favorable variations survive & reproduce at a higher rate
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Variation exists among individuals of a species. Scarcity of resources in an increasing population will lead to competition Individuals with advantageous variations are more likely to survive & reproduce.
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CONVERGENT EVOLUTION DIVERGENT EVOLUTION Type of Environment SimilarDifferent Two or more species Similar but unrelated Related but different ExamplesCactus & euphorbia Red fox & kid fox
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The joint change of two or more species in close interaction. Example: Plants & animals that pollinate them
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Population All members of the same species living in a particular location at the same time Gene Pool Collection of genes for all the traits in a population Allele Frequency Percentage of a specific allele of a gene in the gene pool Genetic Equilibrium Allele frequencies stay the same from generation to generation
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A population will remain in GENETIC EQUILIBRIUM if all of these conditions are met: No Mutations Individuals neither enter nor leave a population Population is large Individuals mate randomly Natural selection does not occur
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Mutation Migration Natural Selection Genetic Drift A phenomenon by which allele frequencies in a population change as a result of random events or change.
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Stabilizing Selection Favors average form (ex. Lizard) Directional Selection Favors one extreme form (ex. Anteaters) Disruptive Selection Favors both extreme forms (ex. Limpets) Sexual Selection
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SPECIATION Formation of a new species.
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Geographic Isolation Physical separation of members of a populations Reproductive Isolation Results from barriers of successful breeding between population groups in the same area
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